384 



MICRO-ORGANISMS IN WATER 



sodium sulphate. Some of the results already obtained 

 are given in the following table : — 



Action of Sunshine on Anthrax Spores suspended in Water 

 (Percy Frankland) 



Spores produced at 18°-20° C. 



I 



3 hours' sunshine, 

 240 per c.c. 

 _l 



r ~\ 



NaCl Na,So, 



1%117 239 



3% 81 218 



10% 46 187 



Darkness, 

 490 per c.c. 



NaCl 

 450 

 384 

 150 



474 

 426 

 622 



Spores produced at 38° C. 



3 hours' sunshine, 

 4 per c.c. 



I I 



NaCl NasSo, 

 1 % 



3 % 1-5 1 



10% 



Darkness, 

 476 per c.c. 



_J 



I I 



NaCl Na,S 



314 390 



132 343 



115 220 



Thus the bactericidal action of light is very con- 

 siderably greater in water containing common salt than 

 in distilled water ; whilst, on the other hand, the addi- 

 tion of sodium sulphate in the same proportions has 

 little or no influence in this respect. An addition of 

 10 per cent, of salt appears to exercise even some 

 bactericidal effect in the dark. The action of this 

 material in enhancing the bactericidal action of light 

 is still more conspicuously brought out in the following 

 experiments : — 



Action of Sunshifie on Anthrax Spores suspended in Water 

 (Percy Frankland) 



Spores produced at 18°-20° C. 



